ATLANTA — Jimmy Carter no longer needs treatment for the cancer diagnosis he revealed in August, a spokeswoman for the former president said on Sunday. Carter, 91, apparently shared the news at one of his regular Sunday School classes at Maranatha Baptist Church in his hometown of Plains, Georgia. Carter announced in August that he had been diagnosed with melanoma that had spread to his brain and laid out a treatment plan, including a round of targeted radiation at the brain tumors and doses of an immune-boosting drug every three weeks.